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 A140886 Triangle read by rows: coefficients of the characteristic polynomials of Redheffer matrices. 0
 1, 1, -1, 0, -2, 1, -1, -1, 3, -1, -1, 1, 3, -4, 1, -2, 5, -1, -6, 5, -1, -1, 5, -6, -3, 10, -6, 1, -2, 11, -21, 13, 8, -15, 7, -1, -2, 13, -33, 38, -11, -19, 21, -8, 1, -2, 16, -52, 86, -69, 7, 34, -28, 9, -1, -1, 12, -54, 124, -155, 90, 13, -56, 36, -10, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 LINKS Eric Weisstein's World of Mathematics, Redheffer Matrix EXAMPLE {1}, {1, -1}, {0, -2, 1}, {-1, -1,3, -1}, {-1, 1, 3, -4, 1}, {-2, 5, -1, -6, 5, -1}, {-1, 5, -6, -3, 10, -6, 1}, {-2, 11, -21, 13, 8, -15, 7, -1}, {-2, 13, -33, 38, -11, -19, 21, -8, 1}, {-2, 16, -52, 86, -69,7, 34, -28, 9, -1}, {-1, 12, -54, 124, -155, 90, 13, -56, 36, -10, 1} MATHEMATICA Redheffer[d_] := SparseArray[{{i_, 1} -> 1, {i_, j_} /; Mod[j, i] == 0 -> 1}, {d, d}] a = Join[{{1}}, Table[CoefficientList[CharacteristicPolynomial[Redheffer[d], x], x], {d, 1, 10}]] Flatten[a] CROSSREFS Cf. A140865. Sequence in context: A115622 A294892 A108886 * A001492 A347049 A054576 Adjacent sequences:  A140883 A140884 A140885 * A140887 A140888 A140889 KEYWORD tabl,sign AUTHOR Roger L. Bagula and Gary W. Adamson, Jul 23 2008 EXTENSIONS Edited by Joerg Arndt, May 30 2021 STATUS approved

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Last modified November 26 21:07 EST 2021. Contains 349344 sequences. (Running on oeis4.)